JERUSALEM - A helicopter crash in Egypt's Sinai desert involving a multi-national observer force killed seven people on Thursday -- five Americans, a French national and a Czech citizen, an Israeli source told AFP. The source, who requested anonymity, said that the crash involved the Multi-national Force and Observers, a peacekeeping force which was co-founded by Israel in 1979 when it signed a peace deal with Egypt, and is not linked to the United Nations.